Backflow preventer



July 13, HORNER BACKFLOW PREVENTER Filed June 21, 1941 M450 /1 Ham/EA,

l N V E N TO R Patented July 13, 1943 UNITED STATES. PATENT OFFICE BAOKFLOW, PREVEhTTER Jason N. Horner, Los Angeles, Calif. Application June 21, 1941, Serial No. 399,118

2 Claims.

This invention pertains to an apparatus for preventing backfiow through a supplyline and is particularly adapted for use in tanks of liquid to prevent the flow of liquid from such tank into the supply pipe in the event pressure of supply fluid is reduced. For purposes of'illustration, the adaptation of the device for use in connection with toilets will be hereinafter described in detail, but it is to be understood that the invention is clearly applicable and effective in many other installations.

In most cities, the water supply lines leading to faucets, drinking fountains and toilets are con-' nected to a common main, and in the past, water normallyheld in the small storage tanks associated with toilets has been siphoned out and back into the water supply lines due to lowering of pressure in the supply line. Where a building, such as an hotel, is several stories high and contains a large number of toilets on each floor, and the water pressure is either out 01f from the main or materially reduced as by excessive use of the water from the main or lower floors, the pressure in the supply pipe leading to a toilet tank in an upper floor will be reduced to such an extent that a'subatmospheric pressure may exist in the line normally supplying water to such upper toilet'tank and water will be siphonedfrom the toilet back into. the water supply 1ine,thus contaminating the water which may be subsequently used for drink-' ing, cooking and other purposes.

An object of the present invention, therefore, is to disclose and provide a simple and effective device for preventing backflow from tanks, so A as to render the contamination hereinabove referred to impossible.

Another object of the present invention is to disclose and provide a simple and effective means of admitting air into the supply line whenever the pressure of supply liquid in such line is reduced.

Other objects and advantages of the invention will become apparent to those skilled in the art from the following description, reference being made to the accompanying drawing showing an exemplary form of the invention. In the drawing:

Fig. 1 is a front view, partly in section, of a usual toilet storage tank equipped with the device of this invention.

Fig. 2 is an enlarged view, partly in section, of the device.

Fig. 3 is a horizontal section taken along the plane IIIIII of Fig. 2.

For example,

In the drawing, a storage tank for flushing water is indicated at i, such tank being provided with a flushing outlet connection 2 adapted to lead to the toilet. The outlet connection 2 is provided with an upstanding overflow pipe 3 extending above the maximum water level indicated at 4. The outlet connection 2 is also pro vided with a valve seat 5 and a valve 6 connected by suitable means such as link I and lever B to the shaft 9 ofan operating handle Hi. A supply pipe for water is indicated at I I, said supply pipe extending through the bottom of the tank and being provided with suitable gaskets at such point of entry. The upper end of the supply pipe ll carries a body portion generally indicated at i2, which body portion includes a fioat actuated valve adapted to discontinue the supply of water to the tank I when the Water level reaches a predetermined maximum. The float is indicated at l3 and is carried by a lever arm I4 pivoted to the body portion l2 at IS, the short end of the lever arm l4 being pivotally connected at Hi to the valve actuating pin H. A downwardly extending outlet pipe 18 permits water from the supply line I l to flow through the body portion [2 and be discharged into the tank I near the bottom thereof. A downwardly extending outlet pipe Iii terminating near the bottom of tank I is desirable since quiet operation is, thereby assured whenever the tank is being refill-ed. i Y r The body portion [2 may be a unitary casting provided with an inlet port in the bottom there: of in communication with a substantially vertical inlet bore 20. The inlet port may be provided with a fitting or closure element 2| connected to the bottom of theintake bore, the fitting being adapted for attachment to the supply line H as by the threads 22. The fitting or closure element may also be provided with an inletseat 23 extending into the bore and spacedfrom the side walls of the bore. The float actuated Valve 24 is movable within the bore 20 and is adapted to seat upon the inlet seat 23. The valve actuating pin ll is adapted to press the valve 24 against the seat 23 when the float I3 is lifted by the water within the tank I.

Laterally displaced with respect to the inlet bore 20 is an outlet port 28 adapted to be connected to the outlet pipe [8. A curving passageway or conduit connects the side of the inlet bore with the outlet port 28. Such passageway may include an upwardly curving portion 29 extending from the side of the inlet bore 20 upwarily to a zone above the level of the seat 23 and in communication with a check valve chamber 39. Another passageway portion 3| then curves downwardly from the check valve chamber 30 to the port 28 and outlet pipe i8.

A check valve is positioned in the passageway (comprising portions 29 and 3|) at above the level of the inlet seat 23. In the simple embodiment shown in the drawing, the chamber 30 is provided with a ball valve 33 adapted to seat upon a seat 34 formed in the side walls of the passageway 29 as it enters the check valve chamber 30. Means are also provided to admit air into the passageway at the top of such passageway and between the check valve and the outlet port 28. Such air inlet may be provided by means of a port formed in the top of the passageway 3|, such port leading to the check valve chamber 39. As shown in the drawing, the air inlet port is provided with a perforated plug 35 threadedly attached to the body portion [2, such plug carrying a seating ring of resilient or elastic material, such as rubber composition, 36 and provided with apertures 31 in communication with the air space in the tank I and above the maximum water level 4 therein.

An examination of the check valve will show that in the event water under pressure is admitted into the supply line H, such water will have a tendency to raise the valve 24 and then flow upwardly through the passageway 29 to lift the ball check valve 33 and place it against the seat 36, thereby closing or discontinuing the communication with the atmosphere. The water may then flow downwardly through the passageway 3! into the outlet pipe I8, thereby filling the tank. When the tank is filled, the float I3 will actuate lever 14 and the valve 24 will be depressed so as to seat upon, the seat 23. The ball valve 33 will then fall to rest upon the seat 34 and air will be admitted through the apertures 3'! into the top of the passageway 3!, thereby causing the water in outlet pipe I8 to assume a level corresponding to the level 4 within the tank I.

In the event the pressure in the supply line H is now reduced to subatmospheric pressure, and even though the valve 24 makes an imperfect seat and leaks,water from the tank I will not be siphoned through pipe I8, passageways, 3| and 29 into the pipe I! because check valve 33 remains seated, and even though the check valve leaks due to imperfect seating, air will be admitted through'apertures 31 into passageway 29 and into line H, thereby preventing contamination of water in line H or therebelow with the water in the tank I.

Means have also been provided in the device of this invention for supplying a small amount of water to the bowl of the toilet while the tank I is being refilled, such means including a small conduit 40 formed in the body portion l2 and communicating with passageway 3|, the conduit ii] being adapted for attachment with a conduit ll! extending into the overflow stand pipe 3.

From the description given hereinabove, it will be evident that a simple, compact, foolproof safety device for preventing backfiow of liquids has been provided. Actual tests have shown the device to successfully operate even though more than 29 inches of vacuum was caused to exist in line I l. Particular attention is called to the fact that the air inlet is at the top of the passageway including portions 29 and 3| and above the level of the float actuated valve seat 23. Moreover. when a ball valve is used, as shown in the drawing, the upwardly curved passageway 29 causes the water supplied by line II to positively raise the ball valve 33, thereby permitting the tank ,to fill with water rapidly and without the necessity of employing relatively high pressure in the supply line I I.

As previously stated, although the device has been described in its adaptation to toilets, it may also be used to advantage in other installations where a similar problem is encountered.

I claim:

1; In an apparatus of the character described: a body portion provided with an inlet port in the bottom and a downwardly directed outlet port laterally displaced therefrom; a vertically extending. inlet bore in said body portion and in communication with the inlet port; a continuous passageway connecting the side of said inlet bore with the outlet port, said passageway gradually curving upwardly from the inlet bore and then curving gradually downwardly to the laterally displaced outlet port; a ball check valve positioned in the passageway and adapted to normally close said passageway at virtually its highest portion; an air inlet communicating with the top of said passageway between the said ball check valve and outlet port, said check valve being adapted to open said passageway and close said air inlet communication when liquid is moving in said passageway from theinlet bore to said outlet port.

2. In an apparatus of the character described, the combination of: a body portion having a vertically extending inlet bore therein and a laterally displaced, downwardly directed outlet port; a continuous passageway connecting the side of the inlet bore with the. outlet port, said passageway gradually curving upwardly from the inlet bore and then gradually downwardly to the late rally displaced outlet port; an enlarged chamber formed in said body portion and intersecting said passageway at virtually its highest portion, said chamber being in communication with the atmosphere; and a ball valve in said chamber adapted to normally close said passageway, said 3 ball valve being liftable by fluid passing through the passageway from the inlet bore to open said passageway to the outlet port and close said atmosphere communication.

JASON N. HORNER. 

